The difference is that the JS version is a sanity check tool that reflects the current state of the API, whatever that may be, and this Silverlight application is finely tuned to the API version 1.0 as published.

1 Answer
1

Source

As an example of how leveraging Soapi.CS and the reusable controls in Soapi.Contrib.Silverlight can increase productivity when writing code against the API, I include the source code for the Soapi.Explore Silverlight application.